Whether you’re a developer building websites or internal applications, or an administrator building the infrastructure to back them, your job doesn’t stop once they’re up and running. Machine failure, releases containing bugs, and growth in usage can all lead to problems that need to be dealt with. To detect them, you need monitoring.
But monitoring can do more than just send you alerts about the things that are going wrong. It can also help you debug those problems and prevent them in the future. So what things should you be monitoring?
Faster web pages lead to happier users. The opposite is also true: increased latency leads to user dissatisfaction and could also be the first warning sign that your system is strained. Launching resource-intensive features often means more user requests being served. As servers die, latency can increase. In fact, latency tends to increase nonlinearly in response to load due to increased contention. Small latency increases today could indicate bigger latency increases in the future; early awareness gives you some time to fix any issues.
Latency is generally measured from two perspectives: your users and your system.
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